Cathodic protection device for marine carburetors

ABSTRACT

A cathodic protection device for marine carburetors wherein the gasket for the power valve of the carburetor is made of a conducting material, such as aluminum, with a sacrificial cathode material secured thereto.

United States Patent 1 Fischer et al.

pppe 2 X\ N 72 7% 2g Nov. 20, 1973 [56] References Cited UNITED STATESPATENTS 2,615,694 10/1952 Olson 261/23 A Primary Examiner-Tim R. MilesAttorney-J. I... Carpenter et al.

[5 7 ABSTRACT A cathodic protection device for marine carburetorswherein the gasket for the power valve of the carburetor is made of aconducting material, such as aluminum, with a sacrificial cathodematerial secured thereto.

2 Claims, 3 Drawing Figures CATHODIC PROTECTION DEVICE FOR MARINECARBURETORS This invention relates to carburetors and, in particular, toa cathodic protection device for marine carburetors.

Due to economic considerations, carburetors for use on internalcombustion engines are normally made with zinc die-cast carburetorhousing components and the fittings used within the carburetor arenormally made of brass, although aluminum may also be used by somemanufacturers in lieu of the zinc. Thus, most carburetors on the markettoday are fabricated using at least two dissimilar metals, such as zincand brass, and under most operating conditions, the use of suchdissimilar metals creates no special problems.

However, when such carburetors are used in marine applications,especially in salt water, corrosion of various components of thecarburetors may occur to the extent that it may be necessary to replacethe carburetor because of such corrosion problems. This is due to thefact that operation of such a carburetor in a salt water marineenvironment entails the probability of ingestion of salt particlescarried in a spray mist. Under normal operating conditions, with theengine in operation, this mist of salt water will mix and be carriedthrough the intake manifold and into the cylinders of the engine to beejected as steam and ash or acid. However, when the engine is shut down,the salt and moisture in the air space above the fuel reservoir of thecarburetor, that is the float bowl, will condense and enter the fuel inthe float bowl. The salt water will separate out and pass through thefuel in the float bowl to lie in the lowermost portions of the floatbowl due to the differences in density between that of the fuel and thesalt containing water.

The salt water thus lying in the bottom of the float bowl creates anelectrolytic cell in which an oxidation or reduction action takes placebetween, for example, the float bowl made of zinc and the varioussubmerged brass fittings in the float bowl of the carburetor. Thisreaction continuesso long as ions are available in the salt water andcan be accelerated by elevated temperature, and reduced exposed area ofthe oxidizing element or increased area of the reducing element.

It is therefore the principal object of this invention to provide acarburetor for marine use with a cathodic protection device therein toprotect the functional material of the carburetor per se.

Another object of this invention is to provide a carburetor for marineuse by providing a gasket for the power valve of the carburetor made ofconductive material with a sacrificial cathode material secured thereto.

A still further object of this invention is to provide a cathodicprotection device which can be easily incorporated into existingcarburetors for use in marine applications.

These and other objects are attained by the'use of a gasket for thepower valve of a carburetor made of a conducting material with thesacrificial cathode material secured thereto.

For a better understanding of the invention, as well as other objectsand further features thereof, reference is had to the following detaileddescription of the invention to be read in connection with theaccompanying drawings, wherein:

FIG. 1 is a view of a conventional two-barrel carburetor with partsbroken away to show details of its construction;

FIG. 2 is a view taken along line 2-2 of FIG. 1 showing the carburetorof FIG. 1, but with a cathodic protection device in accordance with theinvention mounted within the float bowl of the carburetor; and,

FIG. 3 is an enlarged sectional view of a portion of the carburetor ofFIG. 2 taken along line 33 of FIG. 2.

With reference to FIG. 1, there is shown a conventional two-barrelcarburetor 10 not shown in detail since the specifics of this carburetorform no part of the subject invention. The carburetor 10 may be of thetype disclosed in U.S. Pat. No. 2,615,694 issued Oct. 18, 1952 to ElmerOlsen and includes a lower housing 12 and an upper housing 14 to providean enclosed float bowl l6 suitably internally vented by a vent tube, notshown, which leads from inside the bore of the air horn within the upperhousing 14 to the top of the fuel in the float bowl. The carburetor isthus internally balanced through this internal vent because the samepressure causing air to flow through the induction passage in thecarburetor will be acting upon the top of the fuel in the float bowl 16causing fuel to flow. As is common commercial practice, the lowerhousing 12 and the upper housing 14 are formed, for example, as zinccastings.

Fuel from the float bowl 16 is delivered through the main metering jets,each formed by an orifice 18 in a plug 20 threaded into threadedapertures in the lower wall of the float bowl in housing 12, into themain fuel well 22 for delivery via the idle tube 24 or main well tube 26to the throttle 28 controlled induction passage 30 in a conventionalmanner depending on engine operating conditions.

In addition, to achive the proper air-fuel mixtures when more power isdesired or for extreme high speed driving, a vacuum operated powerpiston 32 in the air horn and a power valve 34 located in the bottomwall of the float bowl are used to deliver additional fuel to the mainwell. Through a connecting vacuum passage 36 from the base of thecarburetor to the power piston cylinder 32a in the upper housing 14, thepower piston is exposed to manifold vacuum at all times, a spring 38being used to normally bias the power piston downward. The power pistonis used to effect operation of the power valve 34 positioned within anapertured bushing 40 secured at the bottom of the fuel bowl. The bushing40 has side openings 42 connecting the bore 44 in which the bushing ispositioned with a central opening 46 extending through a valve seat 48normally engaged by the power valve 34 which is urged upward by a spring50 retained by an apertured cup-shaped bushing 52 within the bushing 40.

In response to demand for increased engine power, the power valve 34 iscaused to move down by the spring 38 loaded power piston 32 which isresponsive to a decrease in engine intake suction. Fuel passing throughthe side openings 42 into the bore 44 is metered by an orifice in abushing 54 pressed into a passage 56 in communication with the main well22. As seen clearly in FIG. I, the bushing 40 is provided with anannular flange 58 to engage a gasket or seal washer 60.

Referring now to FIG. 2 in addition to FIG. 1, the bottom of the fuelbowl is formed by two portions, the

shallow bottom wall portion 61 and a deep bottom wall portion 62 todefine a centrally disposed recess within the fuel bowl. At one side ofthe fuel bowl adjacent to the two induction passages is a raised bottomwall portion 64 to provide a plateau for the apertured bushing 40.

In the carburetor structure described above, elements such as the plugand the bushing 40, for example, are conventionally made of brass. Thus,it can be seen that in a conventional carburetor, as illustrated in FIG.1, if salt water from a salt water spray or other means enters the floatbowl of the carburetor and settles to the bottom thereof, this saltwater will form an electrolyte which will be in contact with twodissimilar metals, that is the zinc or aluminum of the lower housing 12and the brass in fittings such as the plug 20 and bushing 40. Corrosionwill then occur with accelerated local concentration cell corrosionoccurring at the junction between these dissimilar metals, in particularat their threaded interconnections. If this occurs repeatedly,sufiicient corrosion will result to adversely affect the operation ofthe carburetor to the extent that replacement of the entire carburetormay be required.

Now in accordance with the invention, there is provided a cathodicprotection device which is ideally suited for use in carburetorsintended for marine use. As best seen in FIGS. 2 and 3, a support panel70, of conductive gasket material, such as aluminum or other materialmore noble than the material of the sacrificial anode 74, is provided atone end with an aperture 72 of a diameter to slidably receive the lowerportion of the bushing 40 so as to form a seal gasket or washer betweenthe annular flange 58 of the bushing and the raised wall portion 64 atthe bottom of the float bowl. This aluminum panel forms, in effect, anenlarged seal washer to replace the seal washer 60 of the type shown inFIG. 1 and, in addition, it is used as an electrical contact between thecarburetor components and. a sacrifi cial galvanic anode and, a supportand protective cover for the anode, as will be described. As shown, thealuminum panel extends out over the lower wall portion 62 of the fuelbowl and is spaced upward therefrom.

To complete the cathodic protection device, a sacrificial anode 74, inthe form of a plate of magnesium or a magnesium alloy, is then securedby aluminum rivets 76 to the underside of the aluminum plate. As bestseen in FIG. 2, the support panel and the anode 74 are contoured toclosely fit the shape of the fuel bowl so as to completely overlie thelower bottom wallportion 62 with only sufficient clearance with the sidewall of the float bowl to allow electrolyte communication with thesacrificial anode 74.

While a sacrificial anode may be securely attached initially, it tendsto be consumed more rapidly at areas adjacent to their metal supports,such as rivets 76 to the support panel 70, and if this deteriorationisallowed to continue to near depletion, the worn anode is easilydislodged and may fall from its support. However, in the arrangementillustrated, the sacrificial anode 74 is retained in the well at thebottom of the float bowl 16 by means of the support panel 70 which ineffect encloses the anode within this well portion at the bottom of thefloat bowl. 7

The cathodic protection device of the subject invention can be readilyinstalled as part of a new carburetor or in a used carburetor, since thesupport panel of this device can form the gasket of the existing powervalve, replacing the original seal washer 60.

What is claimed is:

l. A cathodic protection device for a carburetor of the type having ahousing providing a fuel bowl with a recessed bottom .wall in a portionthereof and a shouldered fuel discharge means threaded in the bottomthereof, said cathodic protection device including a support panel ofconductive gasket material, a sacrificial anode and, fastener meanssecuring said anode to said support panel, said support panel having anaperture therein whereby said support panel is secured by saidshouldered fuel discharge means within the fuel bowl, said support panelforming a gasket between the shoulder of said fuel discharge means andthe bottom of the housing within the fuel bowl, said support panel andsaid sacrificial anode being of a shape to conform to the configurationof the recessed bottom wall of the fuel bowl with the support panelbeing positioned over the sacrificial anode.

2. A cathodic protection device according to claim 1 wherein saidsupport panel and said fastener means are of aluminum and wherein saidsacrificial anode is of a magnesium alloy.

2. A cathodic protection device according to claim 1 wherein saidsupport panel and said fastener means are of aluminum and wherein saidsacrificial anode is of a magnesium alloy.